Agent Based Models: Introduction

Agent Based Models

• Define
  • Individuals
  • Interactions
• Observe Emergent Patterns

Traffic Example

• http://netlogoweb.org/launch#Load
• Heterogeneity and Mean
• Emergent Behaviour
• Policy Making

Traffic Example - 2

When should we bother?

• Benefits:
  • Knowledge is only available at individual level
  • When aggregation is too hard to model mathematically
  • When we want to test what would generate an aggregate pattern
• Cost:
  • Intractable likelihood

Shelling model 1

Shelling model 2

• https://ncase.me/polygons/

Individual Level Policy - 1

Individual Level Policy - 2

Squaring with data

• Estimation problems
  • Intractable likelihood
  • Many parameters
• Techniques
  • Approximate Bayesian Computation
  • Indirect Inference
  • Synthetic Likelihood

Squaring with data 2

Squaring with data 3

Microsimulation

• Gateway drug to ABM
• EUROMOD at Exeter
• Data focused:
  • heterogeneity
  • no interactions

Microsimulation - 1

Microsimulation - 2

Microsimulation - 3

Suggested Reading - 1

Suggested Reading - 2

Suggested Reading - 3